Alcohol consumption has important implications for the management of the HIV epidemic. Several studies suggest that alcohol use is associated with HIV risk and decreased probability of antiretroviral treatment. However, perhaps because of the prominence of injection risks in HIV infection, the role of alcohol in HIV- related processes in drug users has not been adequately investigated. Addressing this problem is a critical public health concern, because alcohol use is prevalent among drug users, and injection drug users constitutes a large proportion of HIV infections. Our long-term goal is to elucidate the role of alcohol in these HIV-related processes among drug user population. We have an opportunity to analyze data collected in three studies from more than 15,000 drug users that can uniquely illuminate the relation of alcohol to HIV in this population over a period of 14 years of the HIV epidemic and across 14 different national settings. We hypothesize that alcohol use: 1) increases HIV infection risk behaviors, 2) reduces receiving antiretroviral treatment and adherence to it, and 3) shows different patterns of association with risk behaviors over time and across countries. We have five specific aims: 1) Determine the association of alcohol use with sexual risk behaviors, by examining the association of levels of alcohol consumption and sexual risks. 2) Determine the association of alcohol use with injection risk behaviors, by assessing the relation of levels of alcohol consumption with injection risks. 3) Determine the association of alcohol use with HIV testing and probability of antiretroviral treatment. 4) Compare the relation of alcohol use and HIV risk behaviors among injection drug users in a "prevention program rich" environment to "prevention program poor" environment. 5) Determine the relationships between alcohol use and HIV risk behaviors in different developing and transitional countries. This goal of our research is to reduce alcohol-related effects on HIV and as such addresses the mission of the agency. The research would also provide critical information for public health policy regarding the role of alcohol in HIV in both the U.S. and in developing and transitional countries. [unreadable] [unreadable] [unreadable] [unreadable]